Re: Video Upgrade

[supertimer@aol.com (Supertimer)]

Rubywand <rubywand@swbell.net> wrote:

>Supertimer wrote:
>
>> Two words: Second Sight.
>> 
>> The Second Sight IS a bunch of PC SVGA chips interfaced to the
>> IIGS graphics.  You get problems...the shadowed video is still
>> limited in speed, and the shadowing takes time...the result is a
>> noticeable choppy quality on a system with a TWGS or ZipGS.
>
>    'Never used a Second Sight card. From the information which has been
>posted, the design begins with a serious oversight-- that is, you can
>not dsiplay all standard IIgs video modes (including double-hires, etc.)
>on the attached SVGA monitor.

Or attached to the standard Apple IIGS RGB monitor...which brings
up the point...the maximum resolution of the IIGS monitor is not
640x200 (the GS 640 SHR mode) but rather 640x400 interlaced.
The Second Sight uses this resolution (via scan line doubling) to
display the normal GS 640 video.

The Second Sight does not support three modes...double hires,
fill mode, and 3200 colors.  Dunno why it does not like DHR.
You can imagine why fill mode won't work...it shadows the GS
video RAM and in fill mode, only an outline of the graphic is in
the GS video memory.  3200 does not work because the shadow
hardware (indeed, the system bus) can't handle the speed of
the updates.

Otherwise, the Second Sight performs as advertised...your
Apple IIGS RGB or SVGA monitor plugs into the card (two
outputs are provided).  The second sight watches the GS
video RAM and duplicates the info in the VGA RAM.  What
you see is actually a VGA duplicate of the GS video...

>> Personally, I think the TurboRez route would be better.  Making
>> the GS like an Amiga (or rather, an old model Amiga) in terms
>> of graphics is easier than making it use PC chips.
>
>     TR is another board it would be nice to know about. What, exactly,
>could/can it do? Will it display all 'old Apple II' and GS graphics and
>text?

TR is a completely different concept.  Put it simply, this is a
blitter card with hardware texture mapping and multiple bitplanes.
It frees up the GS CPU during animations.  It also supports many
more colors per scan line.

The TR plugs into an expansion slot and, unlike the Second Sight,
the video goes out the standard GS RGB port.  The TR does not
interfere with standard GS video modes (no shadowing needed)
and only kicks in when its modes are used.  I think if the TR
beat the Second Sight to the market, things would be much
different today.  Wolfenstein 3D for the GS would run 10x faster
and GS DOOM would be possible...

The big question -- what happened to the TR designs?  The
card was ready to ship when it was cancelled.